In this study, charged π-electronic species are observed to develop stacking structures based on electrostatic and dispersion forces.  iπ–iπ Interaction, defined herein, functions for the stacking structures consisting of charged π-electronic species and is...

Summary Porphyrin–Au III complexes were found to act as π-electronic cations, which can combine with various counteranions, including π-electronic anions. Single-crystal X-ray analyses revealed the formation of assemblies with contributions of charge-by-charge and charge-segregated assemblies, depending on the geometry and electronic state of the counteranions. Porphyrin–Au III complexes possessing aliphatic alkyl chains formed dimension-controlled ion-pairing assemblies as thermotropic liquid crystals, whose ionic components were highly organized by π–π stacking and electrostatic interactions.

The Ni complex of 5-hydroxy-10,15,20-tris(pentafluorophenyl)-porphyrin was synthesized as the precursor of a negatively charged π-electronic system. Deprotonation, which was examined through UV/vis and H NMR spectra, provided an anionic species as the building unit of an ion-pairing assembly in combination with an aliphatic cation.

Phenyl groups were introduced at the b-positions proximal to the meso-hydroxy moiety in hydroxyporphyrin Ni II complexes by oxidized BINAP Pd II complexes. Ion-pairing assemblies of deprotonated p-electronic anions,a nionics ite of which was stabilized by the introduced phenyl moieties with ab ulky cation, were formed. They showedc harge-by-charge assemblies, assembly modes of which were modulated by the anionic building units.Assemblies of charged p-electronic systems can provide diverse functional materials based on the ordereda rrangement of ionic species. [1] Twoi ntrinsic modes of ion-pairing assemblies are observed in charge-by-charge assemblies with alternate stacking of oppositelyc harged species and charge-segregated assembliesw ith stacking of identically charged species (Figure 1a). [2] Various ion-pairinga ssemblies with charge-bycharge and charge-segregated modes have been reported based on genuine p-electronic ions [2b,c,f] along with receptoranion complexes [2b,c,e] and cationic metal complexes [2d,g] as pseudo p-electronic ions. The assembling modes can be controlledb yn oncovalent interactions, depending on designs of charged species and their combinations.I ng eneral,i ti sm uch more challenging to prepare p-electronic anions than p-electronicc ations,b ecause electron-rich anionic states exhibit high reactivity.O ne strategy for the preparation of p-electronic anionsi st he stabilization of an anionic site derivedfrom an acid unit introduced in the p systems( Figure 1b). This strategy has been utilized in dipyrrolyldiketone boronc omplexes, [3] dipyrrolylnitrophenols, [4] and meso-hydroxy-substitutedp orphyrins (MHPs). [2g, 5] MHPs are known as intermediates of heme degradation [6] andc an be oxidizedt or adicals pecies. [7] An effective synthetic method for meso-aryl-substituted MHPs was reported by Arnold and co-workers, [8] followedby several related studies. Stable radical species, as well as p-electronic cations,w ere isolated from MHPs,a nd their spectroscopic, structural, and theoretical propertiesw ere also examined. [9] Although peripheral modifications at the b-positions are essential for further developments in MHP chemistry,s ynthetic methodsf or such modifications have not been investigated. In this work, the introductiono fp henylg roups at the b-positions of MHPs was achieveda nd the resulting deprotonated p-electronica nions formedi on-pairinga ssemblies. Coupling reactions for the modifiedd erivatives werea ccomplished through isolated intermediates, in which the meso-O and b-C atoms coordinated to Pd II via an oxidized 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl (BINAP) ligand.B is-phosphine monooxides (BPMOs)w ith the general formula of R 1 R 2 PÀYÀP(O)R 3 R 4 (Y = spacer) are ligands that are often used in coupling reactions. [10] BPMOsc an stabilizev arious transition metals in low andh igh oxidation states, because they combine both soft (P) and hard (O) Lewis base centers in one molecule. [10a] In some cases,t he intermediateso fc oupling reactions can be isolate...

Dipyrrolyldiketone boron complexes linked by a disulfide bond were synthesized, forming H-aggregated dimers assisted by intramolecular π-π and hydrogen-bonding interactions. The conformations of the dimers, with small C-S-S-C dihedral angles, were examined by UV-vis absorption and H NMR spectra as well as single-crystal X-ray analysis and theoretical studies.